抄録
Reaction of the reduced ricin D with N, N'-o-phenylenedimaleimide produced a cross-linked ricin D which could not be split into its constituent polypeptide chains with reducing reagents. This cross-linked ricin D was as stable as native ricin D and retained the full cytoagglutinating activity, while the toxicity to mice and cultured cells was remarkably de-creased.
The cross-linked ricin D was incorporated into cells in the same manner as native ricin D, but was not degraded by incubation with the lysate of rabbit reticulocytes. From these results, it was inferred that ricin D is split into its constituent polypeptide chains by reduction of the inter-chain disulfide bond in cytoplasm and thus its toxic action is elicited.
